This action funds an NSF National Plant Genome Initiative Postdoctoral Research Fellowship in Biology for FY 2014. The fellowship supports a research and training plan in a host laboratory for the Fellow who also presents a plan to broaden participation in biology. The title of the research and training plan for this fellowship to Michael A. Grillo is "Natural Variation for Specificity Mediated by Signaling Interactions in the Legume-rhizobium Mutualism: A Population Genomic Approach in Medicago truncatula". The host institution for the fellowship is the University of Illinois at Urbana-Champaign and the sponsoring scientist is Dr. Katy Heath.
Training objectives include genomics, plant-microbe interactions, quantitative and evolutionary genetics, association mapping, and population genomics. Broader impacts include promoting Medicago and legumes as a teaching tool in high school biology classes in the Chicago area that serve underrepresented groups in the sciences.
The mutualism between legumes (Fabaceae) and rhizobia (nitrogen-fixing bacteria) is one of the most economically and ecologically important interactions on the planet. A striking feature of this mutualism is the high level of variation for partner specificity, yet the mechanisms that control and maintain such specificity remain poorly understood. This research aims to elucidate the genetic basis of specificity between the model legume, Medicago truncatula, and its primary symbiont, Sinorhizobium meliloti, through an integrative population genomic approach that addresses the following questions: 1) Which signaling genes demonstrate a genomic signature of selection that suggests a role in partner choice, 2) What are the effects of natural allelic variation at signaling genes on partner choice, and 3) What genes control incompatible interactions between Medicago and Sinorhizobium? This line of research will provide a comprehensive examination of natural variation underlying symbiotic signaling in Medicago interactions with its mutualist rhizobia.